Those that want to dampen the Second Amendment often say that civilians shouldn't have military style weapons. There is one small problem, every pistol, every rifle, and even bows were originally designed for the military. It sounds good and those that don't have any strong feelings for firearms this sounds reasonable.
I personally own a 1872 Army (AKA Peacemaker) and a 1911 (designed in 1905 and adopted by the military in 1911). Both these were designed for military use, but civilians have used these for generations for target practice and self-defense.
I was down at the local sporting goods store they had an original 1873 Springfield Armory Trapdoor rifle. The carbine version is what the Seventh Calvary would have had at Gressy Grass (Little Bighorn for us whites, but since Custer lost we should have to refer to it as the Lakota do.) Being a history buff and a student of the Indian wars handling this rifle that most of the time you only get to see behind glass was as seeing a game at the old Tigers Stadium.
One of the many reasons the Seventh Calvary was decimated was these rifles, while extremely accurate at long range was a single shot weapon where the trooper would have open the trapdoor, pull out the spent casing. This wouldn't be a problem if a) the ammo wasn't inferior. The troopers would have to take a knife to digout the casing from breech fairly regular b) the Indians weren't using repeating arms (ie Winchesters and bows). The rifle was obsolete when it was adopted because the Army thought if the troopers had repeating arms they would waste ammunition and there were literally thousands of Springfield Armory muskets left over from the Civil War. The Armory at Springfield, MA reconfigured the rifle making it a breech loader that accepted the brass .45-70 gov't round.
To tie this back to the first paragraph, the semi-auto versions of the AK-47 and M-16 are very different from the assault weapons versions. First off, an assault rifle is capable of full-automatic fire. Technically, the M-16 A-2 (and the carbine version M-4 A-2) are only capable of three round bursts and semi-auto fire thus aren't assault weapons. The AK-47 and the M-16 were designed with the Keep It Simple Stupid principle because it was unknown the amount of training that would be given to a 'recruit.'
The M-16 (M-4 and the semi-auto versions) tear down involves pushing two pins out and removing part of the receiver. I've cleaned one before it is the easiest one I've ever cleaned. There are hunters that use the semi-auto version of the M-16 for coyotes and other varmints. The 5.56 NATO round is barely useful for anything else.
In spite of my sidetracks, I enjoyed my brush with a piece history. If I could have afforded it I would have purchased it...even if it would have sat in my safe.